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Past Questions
The instrument which is cheapest for dc measurement is:
A)
Moving iron
B)
PMMC
C)
Hot-wire
D)
Electro-dynamo
For DC measurement, the moving iron instrument is generally the cheapest. It is rugged, simple in construction, and less costly than PMMC instruments. PMMC is more accurate but more expensive, while hot-wire and electro-dynamo instruments are costlier and used for special purposes. Hence, the correct answer is moving iron.
Thickness of the layer of insulation on the conductor, in cables, depends upon
A)
Reactive power
B)
Power factor
C)
Voltage
D)
Current carrying capacity
The thickness of insulation in a cable is mainly decided by the operating voltage. Higher voltage requires thicker insulation to prevent breakdown and leakage. Current carrying capacity affects the size of the conductor, not the insulation thickness. Reactive power and power factor are not direct factors for insulation thickness.
The emf generated due to nth harmonic component of flux in an alternator will be
A)
n times the fundamental emf
B)
same as fundamental emf
C)
less than the value of fundamental emf
D)
none of these
In an alternator, the induced emf due to the nth harmonic flux depends on the harmonic order and winding factors. Higher harmonics generally produce lower effective emf because the winding and distribution factors reduce the contribution of harmonics compared with the fundamental component. Therefore, the emf generated by the nth harmonic component is less than the fundamental emf. Option (a) is incorrect because harmonic emf is not simply n times the fundamental emf in practical alternators, and option (b) is also incorrect because harmonics do not produce the same emf as the fundamental.
A Ohmmeter is basically:
A)
A ammeter
B)
A voltmeter
C)
A multimeter
D)
None of these
An ohmmeter measures resistance by passing a small current through the unknown resistance and using the current-deflection principle. Structurally, it is basically a sensitive ammeter with an internal battery and suitable series resistance. Hence, the correct answer is A ammeter. It is not a voltmeter, and while a multimeter can measure resistance among other quantities, an ohmmeter itself is essentially based on an ammeter.
The relay best suited for phase fault relaying for medium transmission lines is:
A)
Mho relay
B)
Reactance relay
C)
Impedance relay
D)
None of these
For phase fault relaying on medium transmission lines, the **mho relay** is best suited because it is inherently **directional** and performs well for **longer transmission lines**, but it is also widely used on medium lines due to its good stability on power swings and reduced effect of arc resistance compared with simple impedance relay. The **reactance relay** is more suitable where arc resistance is significant, but it is generally more prone to unwanted operation under load conditions. The **impedance relay** is non-directional and less suitable for transmission line protection because it cannot distinguish fault direction by itself. Hence, the best choice is **mho relay**.
A lightning arrester connected between the line and earth in a power system
A)
Protects the terminal equipment against travelling surges
B)
Protects the terminal equipment against lightning strokes
C)
Suppresses the high frequency oscillations in the line
D)
Reflects back the travelling waves approaching it
A lightning arrester is connected between the line and earth to divert surge current safely to ground when an overvoltage occurs. Its main function is to protect terminal equipment from travelling surges, including those caused by lightning. Option (b) is too narrow because the arrester does not directly protect against only lightning strokes; it protects against the surges produced by them. Option (c) is incorrect because suppressing high-frequency oscillations is not the primary function of a lightning arrester. Option (d) is incorrect because the arrester does not reflect waves; it provides a low-impedance path to earth during surges.
Demand factor is the
A)
Maximum Demand / Average Demand
B)
Maximum Demand / Connected Load
C)
Average Demand / Maximum Demand
D)
Connected Load / Maximum Demand
Demand factor is defined as the ratio of the maximum demand on a system to the total connected load. Therefore, the correct formula is Maximum Demand / Connected Load. Option (a) is incorrect because it is closer to a load factor-related expression, not demand factor. Option (c) is the inverse of load factor, and option (d) is the reciprocal of the demand factor.
Interrupting medium in a contactor may be
A)
air
B)
oil
C)
SF6 gas
D)
any of these
A contactor can use different interrupting media depending on its design and application. Common interrupting media include air, oil, and SF6 gas. Since all three are possible, the correct answer is 'any of these'. Options (a), (b), and (c) are each only a specific case, not exhaustive.
Isolators are used for disconnecting a circuit when
A)
Line is energised
B)
Line is on full load
C)
Line carries no current
D)
Can be operated under any condition
An isolator is a mechanical switching device used to isolate a circuit from the supply only when there is no load current. It is operated after the circuit breaker has opened the circuit, so the line is de-energized and carries no current. It is not meant to interrupt current.
Why others are wrong:
- (a) Line is energised: unsafe; isolators are not used to break an energized circuit.
- (b) Line is on full load: incorrect; isolators cannot safely open load current.
- (d) Can be operated under any condition: false; isolators are used only under no-current conditions.
In outdoor substation, the lightning arrester is placed nearer to
A)
the isolator
B)
the current transformer
C)
the power transformer
D)
the current breaker
In an outdoor substation, the lightning arrester is installed as close as possible to the equipment that needs protection, especially the power transformer. This is because the arrester must divert lightning or switching surges to earth before the surge reaches the transformer. Hence, it is placed nearer to the power transformer. The other options are not the main protected equipment in this context.
What is the actuating quantity for the relays?
A)
Magnitude
B)
Frequency
C)
Phase angle
D)
All of these
A relay operates when its actuating quantity reaches a specified condition. In protective relays, the actuating quantity may be the magnitude of current/voltage, its frequency, or phase angle between quantities depending on the relay type. Therefore, all the given quantities can serve as actuating quantities.
Stones are provided in the substation to:
A)
avoid fire accident by draining oil from transformer if leaks
B)
avoid growing of weeds and plants
C)
provide insulation
D)
All of these
In substations, a layer of stones (gravel) is laid on the ground. It helps in three ways: it prevents weeds and plants from growing, improves drainage and helps reduce fire risk by absorbing/spreading spilled transformer oil, and it also provides a measure of insulation by increasing surface resistance underfoot. Therefore, all the given statements are correct.
California Bearing Ratio (CBR) test is conducted on this layer to determine pavement thickness in modern flexible pavement construction. Identify the layer.
A)
Sub-grade
B)
Granular Sub-base
C)
Water Bound Macadam
D)
Wet Mix Macadam
The California Bearing Ratio (CBR) test is primarily conducted on the sub-grade soil to assess its bearing strength. In modern flexible pavement design, the pavement thickness is determined based on the CBR value of the sub-grade. Granular sub-base, WBM, and WMM are pavement layers, but the CBR test is not mainly used to determine their thickness in this context.
Estimation is computations of the X required and cost likely to be incurred in the construction work. Find the appropriate word for X.
A)
materials
B)
quantities
C)
equipments
D)
labourers
Estimation in civil engineering means calculating the quantities of different items required for a construction work and the probable cost of execution. So the sentence becomes: 'Estimation is computation of the quantities required and cost likely to be incurred in the construction work.' Hence, option (b) is correct. The other options are too narrow: materials, equipments, and labourers are only parts of an estimate, not the general term used here.
Normally 10 % of the amount is deducted from every Contractor’s Bill to be released after a lapse of 6 months (sometimes 1 year or more) from the date of Completion of the work. Such deductions are known as
A)
Security Deposit
B)
Earnest Money
C)
Advance Payment
D)
Performance Guarantee
In PWD/contract works, a percentage of each running/final bill is usually withheld as security and is released after the defect-liability period or after a specified time from completion. This deduction is called the Security Deposit.
Why others are incorrect:
- Earnest Money is deposited before award of work, not deducted from bills.
- Advance Payment is money paid in advance to the contractor.
- Performance Guarantee is a separate guarantee furnished by the contractor to ensure due performance of the contract.
In Mizoram, Administrative Approval for all works under PWD is accorded from the Office of the
A)
Engineer-in-Chief, PWD
B)
Secretary, PWD
C)
Secretary, Finance Department
D)
Minister, PWD
In Mizoram, administrative approval for PWD works is accorded from the office of the Secretary, Finance Department. The Engineer-in-Chief/PWD handles technical matters and execution, but the administrative approval is a finance-sanctioning function. Hence, option (c) is correct.
The perpendicular distance between the corner and hypotenuse of the welded cross-section in a Fillet Weld is known as
A)
legs ofthe weld
B)
size of the weld
C)
effective length
D)
throat thickness
In a fillet weld, the perpendicular distance from the root/inside corner to the hypotenuse (the face of the weld) is called the throat thickness. The legs are the two sides of the triangular weld, and the size of the weld refers to the leg length, not the perpendicular distance. Effective length is the usable length of the weld along the joint.
The term ‘Depreciation’ is used for measuring the
A)
fall in value
B)
rise in value
C)
rate of change of value
D)
profit and loss
Depreciation means the decrease or fall in the value of a property, asset, or structure over time due to wear and tear, age, obsolescence, or other causes. Hence it is used for measuring the fall in value. Options (b), (c), and (d) do not match the standard definition of depreciation.
What type of Weld is also known as Groove Weld?
A)
Fillet Weld
B)
Spot Weld
C)
Pipe Weld
D)
Butt Weld
A groove weld is another name for a butt weld. It is made by welding in a groove between two members, usually with their edges prepared. Fillet weld is used at the junction of two surfaces at right angles, spot weld is for overlapping sheets, and pipe weld is a general term not synonymous with groove weld.
Public Works Department, normally, publish a booklet listing all the likely items of work with per unit cost of such items to be extensively used for preparation of Estimates. Such a booklet is known as
A)
Schedule of Works
B)
Analysis of Rates
C)
Schedule of Rates
D)
Cost Index
Public Works Departments publish a booklet that lists common items of work along with their unit rates for use in preparing estimates. This booklet is called the **Schedule of Rates**.
- **Schedule of Rates**: standard unit rates for materials, labour, and work items used in estimating.
- **Analysis of Rates**: shows how the rate of an item is derived, not the booklet itself.
- **Schedule of Works**: not the standard term for such a booklet.
- **Cost Index**: indicates price level changes, not a list of item rates.
Hence, the correct answer is **(c) Schedule of Rates**.
Apart from riveted rectangular and pressed steel tanks, what shape of steel water tanks are commonly used?
A)
Trapezoidal
B)
Spherical
C)
Cylindrical
D)
V-shaped
Steel water tanks are commonly made in rectangular and cylindrical forms. In steel structures, apart from riveted rectangular and pressed steel tanks, cylindrical tanks are also widely used because they are structurally efficient and suitable for water storage. The other options are not standard common shapes for steel water tanks in this context.
For accuracy, cubic contents of woodwork shall be measured to the nearest of
A)
1.00cum
B)
0.10 cum
C)
0.01 cum
D)
0.001 cum
In standard measurement rules for woodwork, cubic contents are recorded to the nearest 0.01 cubic metre for accuracy. This is the usual precision adopted in estimation and costing. Hence, option (c) is correct. The other options are either too coarse (1.00 cum, 0.10 cum) or unnecessarily fine for standard measurement practice (0.001 cum).
As per IRC Specifications, the minimum Carriageway width for double-lane National Highways in hilly areas is
A)
6.00m
B)
6.50m
C)
7.00m
D)
7.50m
As per IRC standards for double-lane National Highways in hilly and mountainous terrain, the minimum carriageway width is 6.5 m. This is narrower than the usual 7.0 m provided in plains because of the constrained topography in hilly areas. Therefore, option (b) is correct. The other options do not match the IRC minimum for this case.
The primary source of water supply is Precipitation. The most important form of Precipitation is
A)
Rainfall
B)
Snow
C)
Dew
D)
Hail
Precipitation includes rain, snow, hail, sleet, etc. For water supply, the most important form is rainfall because it is the major and most direct source of fresh water that replenishes rivers, reservoirs, and groundwater. Snow and hail are less important as primary water-supply sources, and dew contributes very little.
Plastering shall be measured in
A)
m
B)
sqm
C)
cum
D)
10cum
Plastering is measured by area, since it is applied on the surface of walls, ceilings, etc. Therefore the unit is square metre (sqm). It is not measured in metre, cubic metre, or 10 cubic metre because those are length or volume units, while plastering is a surface work.